What is the minimum amount of total filtration required for an x-ray machine operating above 70 kVp?

What is the minimum amount of total filtration required for an x-ray machine operating above 70 kVp?

• A. 0.5 mm aluminum equivalent
• B. 2.5 mm aluminum equivalent
• C. 1.0 mm copper equivalent
• D. 5.0 mm aluminum equivalent

Answer: (B)

Removing low-energy photons from the beam is essential to protect the patient while keeping image quality. When an x-ray tube operates above 70 kVp, the total filtration (inherent plus added) must be at least 2.5 mm of aluminum equivalent. This minimum filtration ensures the beam is sufficiently “hardened” to reduce skin dose without unnecessarily compromising image quality. So the minimum required filtration is 2.5 mm aluminum equivalent. The other options are either below the required amount, use a different material in a unit not matching the required aluminum-equivalent measure, or exceed the minimum without being the required threshold.

Removing low-energy photons from the beam is essential to protect the patient while keeping image quality. When an x-ray tube operates above 70 kVp, the total filtration (inherent plus added) must be at least 2.5 mm of aluminum equivalent. This minimum filtration ensures the beam is sufficiently “hardened” to reduce skin dose without unnecessarily compromising image quality.

So the minimum required filtration is 2.5 mm aluminum equivalent. The other options are either below the required amount, use a different material in a unit not matching the required aluminum-equivalent measure, or exceed the minimum without being the required threshold.